Prosecutors said Tuesday that in the midst of a fundraising drive for mayoral candidate John Liu, two of his aides met a man named Richard Kong who portrayed himself as a wealthy donor willing to go along with a scheme to skirt campaign finance rules.

City Comptroller John Liu has not been charged and is not expected to testify in the conspiracy case. But the trial could complicate his bid for higher office in what’s turning into a hotly contested mayoral race.